The background description provided herein is for generally presenting the context of the disclosure. Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art or suggestions of the prior art, by inclusion in this section.
D2D applications may provide a scalable and universal framework for connecting proximity peers. There are different technology solutions for D2D applications, e.g., based on WiFi Direct or Near Field Communication (NFC) technology. A special solution that relates to the 3rd Generation Partnership Project (3GPP) is Proximity Services (ProSe) as well as Long-Term Evolution (LTE) Direct.
Support of LTE-based D2D discovery and communications is being studied by the 3GPP radio access network (RAN) working groups (WG). In this regard, it was agreed by the RAN1 WG that D2D discovery and communications within network coverage may be supported on the uplink (UL) spectrum in frequency-division duplexing (FDD) systems, and on UL subframes or potentially downlink (DL) subframes as well for time-division duplexing (TDD) systems.